Boat with means for enclosing the propeller when not in use



Dec. 5, 1944. D.' DANIELSEN 5 BOAT WITH MEANS FOR ENCLOSING THEFROPELLER WHEN NOT IN USE Filed May 28. 1940 2 Sheets-Sheet l I f & 1A4.?

ATTORNEY 5, 1944. D. DANIELSEN 2,364,426

BOAT WITH MEANS FOR ENCLOSING THE PROPELLER WHEN NOT IN USE Filed May28, 1940 2 Sheets-She e t 2 III 111 II INVENTOR WWXTTORNEY Patented Dec.5, 1944 UNITED STATES PATENT OFFICE BOAT WITH MEANS FOR ENCLOSING THEPROPELLER WHEN NOT IN USE Dybwad Danielsen, Buffalo, N. Y.

Application May 28, 1940, Serial No. 337,609

3 Claims. (Cl. 114-67) when the propeller is not inguse, is notdeleteriously alfected as to maneuverability or speed because of thepropeller and propeller opening. Another object of the invention is topermit the propeller to be conveniently and quickly enclosed either whenthe boat is at rest or is under way. Another object of the invention isto provide a simple and inexpensive propeller enclosing means which maybe readily installed on boats of various sizes and proportions, and willbe positive and reliable in action and not liable to leak even when inservice for a considerable period of time. Another object of theinvention is to protect the propelleragainst physical injury when not inuse, and also to prevent its theft when the boat is drawn up on shorefor its winter hibernation. Numerous other collateral objects of theinvention and practical solutions thereof are disclosed in the followingspecification and in the accompanying drawings, wherein:

Fig. 1 is a side elevation of the rear end of a typical auxiliary sailboat.

Fig. 2 is a fragmentary, Vertical, longitudinal, phantom sectionthereof.

Figs. 3 and 4 are enlarged, substantially horizontal, fragmentarysections thereof taken on correspondingly numbered lines of Fig. 2.

Figs. 5 and 6 are enlarged, fragmentary sections similar to Figs. 3 and4 but disclosing a modified form of the invention particularly adaptedto the use of a feathering or a variable pitch propeller.

Similar characters of reference indicate like parts in the severalfigures of the drawings.

At the present time it is accepted as axiomatic by all authorities that,when any sail boat is provided with a motor and a propeller, itsmaneuverability and speed as a sail boat are very materially reduced,because of the variable eddy currents which are formed in and around thepropeller opening due to the lateral pressure of the sails upon thehull. This fact is not so important in the case of a motor boat whichis.

provided with auxiliary sails that are practically never used, but it isof very great importance in the case of an auxiliary sail boat whichisdriven practically all the time by its sails alone and only employs itsmechanical propelling means to a very limited extent.

The present invention permits the use of a propeller in a sail boatwithout in any way detrimentally affecting its maneuverability or speedwhen being driven by the sails alone.

Figs. 1-4

The numeral I0 indicates the hull' of a typical auxiliary sail boathaving a deck ll, a keel or skeg l2, a keel extension l3, a stern timberM, a propeller I5 arranged in the propeller opening it and journaled inthe outboard. propeller bearing I1, a rudder l8 and a propeller shaftl9. Preferably set in flush with eachouter, vertical, longitudinalsurface of the keel extension 13 are two pairs of substantiallyvertical, parallel guide bars 20, 2| and 20, 2| which are secured inplace by screws 22 or otherwise, and are preferably of U shaped crosssection as shown in Fig. 4. Slidably arranged in these pairs of guidebars are rectangular, sheet metal covering plates 23, 23 which arepreferably rabbeted at 24, '24 along their substantially vertical,longitudinal edges so as to slidably engage with the grooves of theircompanion guide bars 20, 2| and 20, El with their outer faces flush withthe outer faces of their companion guide bars, and hence also flush withthe outer faces of the keel extension 13. These covering plates areadapted to be raised or lowered so as to cover or uncover the propelleropening [6 and its propeller IS. The lower face of said propelleropening is preferably sheathed with a metal striking strip 25 which maybe secured in place by fiat head screws 26, or otherwise, to the keelI2. This striking strip prevents the lower edges of the covering plates,from chewing up the keel when they are inadvertantly forced down withexcessive pressures. V

Said covering plates project up into the hull ll] of the boat thru apair of thin, obliquely disposed but substantially longitudinal slits27, 21 which are suitably formed in the stern timber M in alignment withtheir companion guide bars 20, 2| and 20, 2!. Arranged in alignment withsaid slits are a pair of substantially vertical wells 28, 28' which arepreferably formed of sheet metal and have welded to their lower endssuitably formed companion flanges 30, 30' which are secured by screws orbolts 3|, 3| to the upper face of the stern timber M. If desired a thinsoft gasket (not shown) may be interposed between the lower faces ofsaid flanges 3t, 30 and the upper face of the stern timber I4 so as tomore positively ensure against any leakage thru these joints. The upperends of the wells are preferably braced to the hull of the boat bysuitable cross timbers 32 and 33.

Secured detachably by bolts 34 or otherwise within the upper ends ofeach of wells 28, 23 is a thrust block 35 which is provided with a hub36 that rotatably receives the upper end of a companion; longitudinallydisposed screw 31 or 31. Each of these screws is restrained againstvertical movement relatively to its companion thrust block by suitablethrust collars 38, 39 which respectively bear against the upper andlower faces of their companion thrust blocks and are pinned or otherwisesuitably secured to their companion screws.

Manual rotation of each of these screws is effected by a detachablehandle 40, the hub of which fits over the upper squared ends of thescrews 31, 31. To enable this operation to be effected, the deck ll ofthe boat is provided with a suitable stern hatch 43. The lower end ofeach screw 31, 31 is threaded thru a companion cleat 44, 44 which issuitably secured to the upper end of its companion covering plate 23,23. Thus, when the detachable handle 40 is placed upon the one or theother of the screws and is manually rotated, its companion cover plate23 or 23' is either raised or lowered, as may be desired. To prevent anywhipping of the lower ends of each of these screws when its companioncovering plate is in its extreme upper position, the extreme lower endof said screw is of reduced, cylindrical form and is journaled in acompanion brace tongue 45, which is formed integrally with its companionflange 30, 30' and extends a suitable distance into the bore of itscompanion well. These brace tongues do not, however, interfere withtheir companion covering plates and hence, when it is desired to removethe same, the detachable bolts 34 of each thrustblock 35 are removed andsaid thrust block, together with its companion screw 31 or 31 andcovering plate 23 or 23' is slipped up and out of its companion well 28or 28' thru the stern hatch opening 46. When these parts are slippedback into place the cleat 44 or 44 of each covering plate guides thelower, reduced, cylindrical end of its companion screw into its bearingin its companion brace tongue 45 or 45'. In actual practice, from acommercial point of View, it will probably never be found necessary toremove the covering plates, and hence it is deemed practical toeliminate the hatch opening 46 entirely and have the two screws 31, 31project up thru the deck ll thru suitable openings.

To accommodate the screws 31, 31' and their companion cleats 44, 44, thewells are bulgedout at 41, 41' and their companion flanges 30, 30'suitably curved outwardly at 48, 48 to conform therewith. Such aconstruction provides a means of enclosing the propeller withoutrequiring any glands which are apt to leak, there being only one placewhere leaks could possibly occur in the present construction, namely,the joint between the flanges 30, 36' and the top face of the sterntimber. This joint being stationary, and kept tight by a considerablenumber of screws or bolts 3|, 3|, no leakage is likely to occur evenafter the boat has been in service a considerable length of time.

It should be noted that advantage is taken of this hatch opening 46 togain access to the quadrant 50 of the rudder l8 and to its cables 5|, 52and also to its squared upper end 53. Thus, if one or other of saidsteering cables should break, a

- 64, 64, said brace wrench or other suitable tool may be engaged withsaid squared end 53 of the rudder and the boat temporarily steered inthis manner.

The stock 54 of the rudder i preferably of hollow, tubular form, asillustrated, and is rotatably mounted in the usual manner at its upperend in a rudder tube 55 which is threaded at its lower end 56 into thestern timber l4 and is braced at its upper end by the hull cross timber33. The lower end of said rudder stock 54 is provided with the usualdetachable heel bearing 51 which is journaled in the heel 58 of the keel[2.

The blade portion of the rudder is, however, of novel design. Securedpreferably by welding at 60 to the rear face of the rudder stock 54 area plurality of sheet metal, cantilever brace bars 6 I, 62 and 63 whichtaper off to zero at their rear ends. Secured by welding or otherwise tothe outer edges of these cantilever brace bars is a pair of rudderplates 64, 64 whose front, sub stantially vertical, straight edges aresecured by welding or otherwise at 65 to the outer rear faces of therudder stock 54. The curvilinear rear edges 66 of these rudder platesare welded or otherwise secured together so as to provide a strong,light, stream-lined rudder. As illustrated, the cantilever brace bars61, 62 and 63 are disposed perpendicular to the rudder stock 54, but, ifit is desired to ploy very thin rudder plates ars may be disposedsubstantially parallel to the flow of the water at this point so thatdeformations of the rudder plates 1 will not increase the skin frictionof the rudder.

This same effect may be obtained by filling the hollow interior of therudder with wood or water. In the latter case it is consideredpreferable to seal the water in, but it is deemed to be satisfactory toprovide a plurality of apertures which will allow the rudder toautomatically fill itself when the boat is put in the water and toreduce substantially to zero the differences in pressure on oppositesides of each rudder plate.

In combination with the present invention it 5 preferable that a twobladed propeller be used, as

shown. This is because, in the first place, such a propeller enables thecover plates 23, 23 to be placed so close together that their frontedges are positioned flush with the keel extension l3 as shown in Fig.4. In the second place, when a two bladed propeller is used, it doesnot, with the present invention, have to be turned to any certainposition before lowering the cover plates 23,

23. This is because, if one of the cover plates is lowered completelybefore its mate is lowered, the first named cover plate willautomatically engage with the blades of the propeller and turn it to theposition shown'in Fig. 4, whereupon the other cover plate may be loweredwithout danger of interference on the part of the propeller. Also a. twobladed propeller, if properly balanced, is more efficient than a threeor four bladed propeller, if there is suflicient space to swing it.

When the cover plates are thus lowered, no eddy currents can form in thepropeller opening "5 and hence the boat can be handled as sweetly as thoit had no propeller or propeller opening at all. While such an enclosingof the propeller is of particular advantage in an auxiliary sail boat itis to be understood that the invention is applicable to otherboats aswell. For instance when applied to a motor driven dinghy, such a dinghymay be towed astern with a minimum of danger of injuring the propellerbecause of floating logs, etc. Also in the case of any boat In certainhull constructions the propeller is located in a propeller pocket whichis only open at one side. It is obvious that such a constructionrequires only a single cover plate to close said pocket.

Figs. and 6 In the previously described construction of Figs. 14 thewells 28, 28' were shown as having individual flanges 30, 30' and havingtheir screws 31, 31' located unsymmetrically inside their cover plates23, 23". Such a construction, while having certain advantages, does notpermit the cover plates to be placed as close together as is desirablein some boats having a narrow keel Ma and a narrow feathering oradjustable pitch propeller l5a. In such an installation it is deemeddesirable to mount both of the Wells. 28a, 28a on a single flange 30asecured by screws 3la to the top face of the stern timber I 4a and withthe screws 31a, 31a located symmetrically outside their companion coverplates 23a, 23a. Otherwise the construction is the same as that of Figs.1-4.

I claim as my invention:

1. An auxiliary sail boat having a keel extension provided with apropeller opening and having a stern timber provided with a pair ofIongitudinal slits whose outer faces are in alignment with the outerfaces ofsaid'keel extension; a propeller arranged in said opening; apair of guide bars on each side of said keel extension in proximity tothe sides of the opening thereof; a

pair of sheet metal wells arranged in alignment With said slits and eachhaving a longitudinal bulge and also a flange at its lower end forattachment to the upper face of the stern timber; a brace tongue on eachflange projecting into the bulge of its companion well; a detachablethrust block arranged in the upper end of each well; a covering platearranged in each well and engaging with its companion pair of guidebars; a cleat on each covering plate arranged in the bulge of itscompanion well; and a screw also arranged in the bulge of each of itscompanion wells and journaled at its opposite ends in its companionthrust block and brace tongue andintermediately threaded thru itscompanion cleat.

2. An auxiliary sail boat having-a propeller-receiving opening extendingtransversely thru its hull and comprising: a propeller arranged in saidopening and rotatable on an axis which lies in a vertical planepositioned longitudinally of the boat; a pair of covering (platesslidably disposed at the opposite ends of said opening; a pair of thrustblocks detachably connected to the hull of the boat; and a pair ofactuating screws journaled in said thrust blocks and in threadedengagement with said covering plates.

3. An auxiliary sail boat having a slit thru its hull andhaving a skegdisposed below said slit and having a propeller-receiving opening insaid skeg and comprising: a propeller arranged in said opening androtatable on an axis which lies in a vertical plane positionedlongitudinally of the boat; a well secured to the boat in align-- mentwith said slit; 3, covering plate arranged in said well and said slit;and an actuating screw journaled in said well and in threaded engagementwith said covering plate.

DYBWAD DANIELSEN.

